christopher diggins wrote:
3.9(2) says: For any complete POD object type T, whether or not the object holds a valid value of type T, the underlying bytes (1.7) making up the object can be copied into an array of char or unsigned char.36) If the content of the array of char or unsigned char is copied back into the object, the object shall subsequently hold its original value.
This has nothing to do with void* and char*, but rather with all POD's.
This clearly implies char arrays are stringently aligned.
Not to me, it doesn't! It doesn't say "can be copied into *any* array of char". And it doesn't say you can use reinterpret_cast to use the char array as an object of T, it says you can store the bytes there then copy them back into a T, without loss of information. You are implying this is OK: #include <cstring> typedef int T; struct S { char a1[3]; char a2[sizeof(T)]; }; int main() { T t; S s; std::memcpy(s.a2, &t, sizeof(T)); T* p = reinterpret_cast<T*>(s.a2); return *p; } That's nonsense. S.a2 is not correctly aligned for an int. jon